OPERATION GREENHOUSE. Scientific Director's Report of Atomic Weapon Tests at Eniwetok, 1951. Annex 6.5. Interpretation of Survey-Meter Data,
NAVAL RADIOLOGICAL DEFENSE LAB SAN FRANCISCO CA
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This is the Scientific Directors Report of Atomic Weapon Test at Enuivetok, 1951. Under laboratory conditions a study of survey-instrument response to fission-product activity was made. This study involved a knowledge of beta-ray energy, gamma-ray energy, and beta-ray and gamma-ray dose rates associated with fission-product radiation fields. Fission-product activity was collected on aluminum plaques which were flown through the radioactive cloud following each of four bursts. These plaques were flown to the Laboratory for the work done. Beta-ray dose rates were determined with specially constructed beta-ray surface chambers previously calibrated with beta-ray isotopes. Using aluminum absorbers, beta-ray absorption curves were run and compared with similar absorption measurements obtained using known beta-ray isotopes. Gamma-ray dose rates were obtained by shielding out the beta-ray contribution. The response of various types of commercially available G-M counters and ion-chamber counters to fission-product beta-ray and gamma-ray was studied. Changes in beta-ray energy were studied for the period from 44.6 to 215.7 hr. It was found that the beta-ray absorption curve could be reproduced by a high-energy and low-energy component of beta radiation. Laboratory determination of effective gamma-ray energies using half-value-layer measurements by means of aluminum, copper and lead filters showed the energy to be dependent upon the absorber used.
- Nuclear Radiation Shielding, Protection and Safety
- Radioactivity, Radioactive Wastes and Fission Products
- Nuclear Weapons